package com.library.lms.utils;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

public class IdentifyCodeUtils {
        //设置图片宽
        private int width = 95;
        //设置图片高度
        private int height = 25;
        //设置干扰线数量
        private int lineSize = 40;
        //随机产生数字和字母组合的字符串
        private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        private Random random = new Random();

        /**
         * 获得字体
         */
        private Font getFont() {
            return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
        }

        /**
         * 获得颜色
         */
        private Color getRandColor(int fc, int bc) {
            if (fc > 255) {
                fc = 255;
            }
            if (bc > 255) {
                bc = 255;
            }
            int r = fc + random.nextInt(bc - fc - 16);
            int g = fc + random.nextInt(bc - fc - 14);
            int b = fc + random.nextInt(bc - fc - 18);
            return new Color(r, g, b);
        }

        /**
         * 获取验证码
         *
         * @return
         */
        public String getIdentifyCode() {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < 4; i++) {
                char c = randString.charAt(random.nextInt(randString.length()));
                buffer.append(c);
            }
            return buffer.toString();
        }

        /**
         * 生成随机图片
         *
         * @param identifyCode
         * @return
         */
        public BufferedImage getIdentifyImage(String identifyCode) {
            //BufferedImage类是具有缓冲区的Image类，Image类是用来描述图像信息的类
            BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
            //产生Image对象的Graphics对象，改对象可以在图像上进行各种绘制操作
            Graphics graphics = image.getGraphics();
            //图片大小
            graphics.fillRect(0, 0, width, height);
            //字体大小
            graphics.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
            //字体颜色
            graphics.setColor(getRandColor(110, 133));
            //绘制干扰线
            for (int i = 0; i <= lineSize; i++) {
                drawLine(graphics);
            }
            //绘制随机字符
            drawString(graphics, identifyCode);
            graphics.dispose();
            return image;

        }

        /**
         * 绘制字符串
         */
        private void drawString(Graphics g, String identifyCode) {
            for (int i = 0; i < identifyCode.length(); i++) {
                g.setFont(getFont());
                g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
                        .nextInt(121)));
                g.translate(random.nextInt(3), random.nextInt(3));
                g.drawString(String.valueOf(identifyCode.charAt(i)), 13 * i + 20, 18);
            }


        }

        /**
         * 响应验证码图片
         *
         * @param identifyImg
         * @param response
         */
        public void responseIdentifyImg(BufferedImage identifyImg, HttpServletResponse response) {
            //设置响应类型，告诉浏览器输出的内容是图片
            response.setContentType("image/jpeg");
            //设置响应头信息，告诉浏览器不用缓冲此内容
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expire", 0);
            try {
                //把内存中的图片通过流动形式输出到客户端
                ImageIO.write(identifyImg, "JPEG", response.getOutputStream());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


        /**
         * 绘制干扰线
         */
        private void drawLine(Graphics graphics) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(13);
            int yl = random.nextInt(15);
            graphics.drawLine(x, y, x + xl, y + yl);
        }





}
